Organophosphorothioate compounds and method of preparing same



United States Patent lice This application is a continuation-in-part application of copending US. application Serial No. 11,442, filed February 29, 1960, now abandoned.

The present invention relates to organophosphorothioate compounds and their preparation. More particularly the instant discovery concerns the preparation of organophosphorothioate compounds by bringing together thiophosphate esters of the formula with an organophosphoric acid salt of the formula to produce the corresponding salt of the formula RiAl SM (C) 0 AzRz which, in turn, may be reacted with an organic halide or sulfate corresponding to the formula (R) Y to produce a product ester conforming to the formula R A SR (D) 0 Ann In the above formulae the symbols have the following a significance:

A through A represent oxygen or sulfur; R represents lower alkyl or phenyl; R and R represent lower alkyl,

3,309,371 Patented Mar. 14, 1967 R and R represent lower alkyl;

M represents an alkali metal ion, including Na, K, Li, ammonium, and substituted ammonium, such as mono, diand tri-lower (C C alkyl ammonium, cyclohexylammonium, dicyclohexylammonium, and the like; v

R represents lower alkyl Y represents halogen or sulfate; 11 is the value 1 or 2.

A typical embodiment involves the reaction of 0,0- dimethyl S-(N-methylcarbamoyl)methyl phosphorodithioate with potassium diisopropyl phosphorodithioate in methyl ethyl ketone to produce potassium O-methyl S-(N- methylcarbamoyhmethyl phosphorodithioate as follows:

3 In turn, potassium O-methyl S-(N-methylcarbamoyl) methyl phosphorodithioate is reacted with dimethyl sulfate to produce the corresponding ester as follows:

Quite unexpectedly, the present invention provides a novel, straightforward and unobvious process for produc ing new compounds and very desirable salts in good high yields, which salts are readily convertible to their corresponding esters. These esters manifest significant insecticidal and miticidal activity, as will be seen hereinafter.

Surprisingly enough, it has been discovered that when R., and R of formula (B) above are both methyl, a rearrangement takes place in the fashion shown in the following typical example:

It appears that the reactant ester derivative (1) in the equation above undergoes a second reaction with the phosphoric acid salt derivative (2), and so on, until an equilibrium is reached and, in the instant case, product (4) conforming to formula (D), above, is produced. Equilibrium had not been reached in formula (3), above, because there was still a labile .CH .group attached to oxygen which was capable of reacting with sulfur in the moiety of (5). If the alkyl group on oxygen were other than methyl, say it were propyl, then formula (5) would have been the product.

Obviously, in the anomalous reaction just shown it is not necessary to react the intermediate salt (1) or (5) with an (R) Y reactant, such as methyl sulfate, since the by-products (2) and (3) function much the same way.

Generally, the reactants are brought together in the presence of an inert solvent, i.e., a solvent which under the conditions of the reaction is inert with respect to the reactants and the reaction products. Typical solvents are water, organic solvents, such as methyl ethyl ketone, acetone, acetonitrile, carbon tetrachloride, methyl alcohol, ethyl alcohol, and ethoxyethanol, and other similar solvents.

It is an advantage of the present invention that the intermediate salts may be recovered after the first step (1) and subsequently reacted in a second step (2) with (R) Y compounds to produce their corresponding esters. As will be seen hereinafter, however, an in situ process (3) may be employed whereby the reactants (A), (B) and (R) Y of the generic equation, above, are brought together in a single-shot method and the corresponding ester (D) recovered, without the necessity of recovering (C). (For the meanings of (A), (B), (C), (D) and (R),,:( see columns 1 and 2, above.)

The reactants may be brought together at room temperature (20 C.25 C.) in any of these steps, i.e. (l), (2) or (3), but a wide range of temperatures is contemplated herein, from about 15 C. to about C. As a practical matter, however, it is preferred to operate at the boiling point of the solvent employed.

While particularly desirable results are obtained at atmospheric pressure, it is significant to note that subatmospheric or super-atmospheric pressures may be employed without upsetting the nature of reactions (1), (2) or (3). Similarly, the reactants of the present in vention may be brought together in any sequence and the process carried out in a continuous, semi-continuous or batch manner.

While equirnolar proportions of the reactants are suitable and generally preferred, large or small excesses of any of the reactants contemplated herein may be employed without upsetting the nature of the reactions. As always, however, cumbersome excesses are impractical.

The present invention will best be understood by means of the following illustrative examples:

EXAMPLE I Dicyclohexylammonium O-methyl S-(N-met/lylcarbamoyhmetllyl phosphorodithioate A solution of 4.58 grams (0.02 mole) of 0,0-dimethyl- S-(N-methylcarbamoyl)methyl phosphorodithioate and 7.91 grams (0.02 mole) of dicyclohexylammonium 0,0- diisopropyl phosphorodithioate (melting point 133 C.- C.) in 200 milliliters of carbon tetrachloride is allowed to stand at room temperature for two hours, then heated under reflux with stirring for 2 /2, hours and allowed to stand overnight at room temperature. Removal of the solvent under vacuum leaves a viscous oil which on trituration with hexane gives a solid. Two recrystallizations from carbon tetrachloride yield 3.2 grams (40 percent by weight of theory) of analytically pure product dicyclohexylammonium Omethyl S-(N- methylcarbamoyDmethyl phosphorodithioate, melting point 111 C.-114 C.

EXAMPLE 11 Potassium O-methyl S-(N-methylcarbamoyl)methyl phosphorodithioate The solvent ,5. comprising, as identified by nuclear magnetic resonance spectroscopy, product potassium O-methyl S-(N-methylcarbamoyl)methy1 phosphorodithi'oate.

EXAMPLE III Dicyclohexylammonium O-ethyl O-(4-nitr0phenyl) phosphorothioate 0,0 diethyl O (4 nitrophenyl) phosphorothionate (7.28 grams, 0.025 mole) is added to a refluxing solution of dicyclohexylammonium 0,0- diisopropyl phosphorodithioate (9.88 grams, 0.025 mole) in 125 milliliters of methyl ethyl ketone. Refluxing is continued for six hours, after which the solvent is removed under vacuum. The resulting orange liquid residue is poured into 200 milliliters of hexane to give a cream-colored solid which is collected by filtration. This solid is then taken into 200 milliliters of fresh hexane and heated to boiling to dissolve unreacted dicyclohexylammoni-um diisopropyl phosphorodithioate. The resulting insoluble solid amounts to 6.52 grams (36.7 percent by weight of theory) of product dicyclohexylammonium O-ethyl O-(4-nitrophenyl) phosphorothioate. An analytically pure product which melts at 160 C.-161 C. is recovered after recrystallization from benzene heptane.

EXAMPLE IV Cyclohexylammonium O-ethyl O-(4-nitr0phenyl) phasphorothioate Cyclohexylammonium 0,0-diisopropyl phosphorodithioate (62.7 grams, 0.2 mole) is dissolved in methyl ethyl ketone (-0 milliliters) and heated to reflux. Then 0,0-diethyl O-(4-nitrophenyl) phosphorothionate (58.2 grams, 0.2 mole) is added, and refluxing continued for six hours. Solvent is removed in vacuo and the liquid residue extracted several times with boiling hexane to remove by-products and unreacted starting materials. The insoluble orange oil, on treatment with ether, gives crystalline product cyclohexylammonium O-ethyl O-(4-nitrophenyl) phosphorothioate (36.3 grams, 50 percent by weight of theory), melting point 106 C.108 C.

EPQXMPL'E IV(a) T riethylammonl'um O-ethyl O-(4-nitrop henyl) phosphorothioate The process of Example 1V, above, is repeated in every essential respect with the exception that triethy-lammo- 6 used in lieu of cyclohexylammonium 0,0-diisop'ropyl phosphorodithioate and the corresponding dibutylammonium O-ethyl O-(4-nitrophenyl)phosphorothioate recovered in significant yields.

EXAMPLE IV(c) H exylammonium 0 ethyl O-(4-nitr0phenyl) phosphorothioate The process of Example IV, above, is repeated in every essential respect with the exception that hexylammonium 0,0-diisopropyl phosphorodithioate (0.2 mole) is used in lieu of cyclohexylammonium 0,0-diisopropyl phosphorodithioate and the corresponding hexylammonium O-ethyl O-(4-nitrophenyl) phosphorothioate recovered in significant yields.

EXAMPLE V Potassium 0,0-dimethyl phosphorothioate Potassium 0,0-diisopropyl phosphorodithioate (12.6 grams, 0.05 mole) is dissolved in 100 milliters of methyl ethyl ketone and heated to reflux (81 C.). 0,0,0-trimethyl phosphorothionate (7.8 grams, 0.05 mole) is added and the mixture maintained at 81 C. for four hours. Crystals separate when the solution is cooled, giving 5.7 grams of product (73.3 percent by weight of theory) potassium 0,0-dimethyl phosphorothioate.

EXAMPLE VI Potassium 0,S-dimethyl phosphorodithioate Example VI, above, is repeated in every essential respect with the exception that potassium 0,0-diethyl phosphorodithioate is used in lieu of potassium 0,0-diiso propyl phosphorodithioate. Similarly, product potassium O,S-dimethyl phosphorodithioate is recovered.

nium 0,0-diisopropyl phosphorodithioate (0.2 mole) is used in lieu of cyclohexylamrnoniu m 0,0-diisopropyl phosphorodithioate and the corresponding triethylammonium O-ethyl O-(4-nitrophenyl)phosphorothioate recovered in significant yileds.

EXAMPLE IV(b) Dibutylammonium O-ethyl 0+(4-nitr0phenyl) phosphorothioate The process of Example IV, above, is repeated in every essential respect with the exception that dibuty1ammonium 0,0-diisopropyl phosphorodithioate (0.2 mole) is 75 A solution of 0,0,S-trimethyl phosphorodithioate (1.72 grams, 0.01 mole) and potassium 0,0-dimethyl phosphorodithioate (19.6 grams, 0.1 mole) in 700 milliliters of methyl ethyl ketone is heated under reflux during thirty hours The solution is then decanted from some inorganic material and cooled to 0 C. The resulting crystals, 8.7 grams, melting point 214 C.215 C., constitute 44.4 percent by Weight of theory of (CHsS)2i -OK Solvent is evaporated from the filtrate and the residual syrup treated with chloroform until a white powder forms.

This is collected by filtration, 8.3 grams, and constitutes 42.3 percent by weight of theory of CHsS O l SK CHsO EXAMPLE IX Sodium O-belzzyl-O-elhyl phosphorothioate Equimolar quantities of O-benzyl 0,0-diethy1 phosphorothionate and sodium 0,0-diisopropyl phosphorodithoate are dissolved in methyl ethyl ketone and heated under reflux for two hours. Solvent is removed in vacuo and the residue treated with chloroform. An equal volume of ether is added and the product salt sodium benzyl-O-ethyl phosphorothioate is recovered by filtration.

EXAMPLE X S [I,Z-bis(cthoxycarbonyl) ethyl] O,S-dimethyl phosphorodithioate A solution of 66 grams (0.2 mole) of S-[1,2-bis- (ethoxycarbonyl)ethyl] 0,0-dimethyl phosp-horodithioate and 50.5 grams (0.2 mole) of potassium diisopropyl phosphorodithioate in 200 milliliters of acetone is heated under reflux for one hour. After evaporation of the solvent under reduced pressure, the residue is extracted with hexane and acetone to remove 0,0-diisopropyl S-methyl phosphorodithioate. The clear glassy residue potassium S-[1,2-bis(ethoxycarbonyl)et-hyl] 0- methyl phosphorodithioate is dissolved in 100 milliliters of water and treated with excess methyl sulfate in two portions. The first portion (25.2 grams, 0.2 mole) is added gradually with cooling, the temperature being kept below 25 C. After a half-hour at room temperature, the product layer is separated and the aqueous layer treated with the same quantity of methyl sulfate as previously, this time at 45 C. The reaction mixture is allowed to cool to room temperature and the two product layers are combined, freed of excess methyl sulfate under vacuum, and dried over sodium sulfate. The isomerized reactant is an oil, shown by nuclear magnetic resonance spectroscopy to contain the P-OCH and P-SCH moieties in equal amounts, and called S-[1,2-bis(ethoxycarbonyl)ethyl] O,S-dimethyl phosphorodithioate. Analytically pure material may be obtained by molecular distillation, 1.4982.

phorodithioate (22.9 grams, 0.1 mole) and potassium diisopropyl phosphorodithioate (25.2 grams, 0.1 mole) are heated in 500 milliliters of water at 75 C. for 1 /2 hours. The reaction mixture is cooled, the layers separated, and the aqueous phase extracted with three SO-milliliter portions of ether. The ether extracts are combined with the non-aqueous phase, dried and stripped, yielding 19.2 grams (84 percent by weight of theory) of 0,0-diisopropyl S-methy1 phosphorodithioate. Residual dissolved ether is removed from the aqueous phase under vacuum, and to this aqueous solution of potassium O-methyl S (N-methylcarbamoyl)methyl phosphorodithioate is added 12.6 grams (0.1 mole) of methyl sulfate and the heterogeneous system stirred rapidly for one hour at 40 C. The cooled reaction mixture is extractedwith two 100- milliliter portions of ether, which are discarded, followed by five 100-milliliter portions of chloroform. The chloroform extracts are dried over magnesium sulfate and the solvent removed under vacuum, leaving the product as a viscous straw-colored oil (10.6 grams, 47 percent by weight of theory). Analytically pure material, n 1.5511, is obtained by low-temperature crystallization. The structure is proven by a combination of infrared and nuclear magnetic resonance spectroscopy to be O,S- dimethyl S-(N-methylcarbamoyl)rnethyl phosphorodithioate.

EXAMPLE XII O,.S '-dimethyl S-(N-uiethylcarbamoyl) methyl phosphorodithioate The compound of Example XI is prepared by the reaction between potassium O,S-dimethyl phosphorodithioate (6.86 grams, 0.035 mole) and 2-chloro-N-methylacetamide (3.76 grams, 0.035 mole) in a heterogeneous system consisting of 5 milliliters of water and 10 milliliters of chloroform. There is isolated from the chloroform layer percent of an oil whose infrared spectrum is virtually identical with that of the compound of Example XI.

EXAMPLES XIII-XVIII The products of some of the above examples are reacted under the conditions contemplated herein and given hereinabove with equimolar amounts of (R),',Y reactants as shown in the following table to yield their corresponding product esters:

EXAMPLE XI QS-dimethyl S- (N-methylcarbamoyl) methyl phosphorodithioate 0,0-dimethyl S-(N-methylcarbamoyl)methyl EXAMPLES XIXXXXVII The following table shows still more in situ preparations which are carried out essentially as in Example X,

phosabove, only the reactants being changed as indicated:

13 Obviously, as indicated hereinabove, the bracketed intermediate products may be recovered and reacted with the(R) Y reactant to produce the final product.

14 the main organic fraction, and solvent plus unreacted ethyl sulfate are recovered by distillation. The product S-ethyl O-methyl S-[1,2 bis(ethoxycarbonyl)ethyl] phosphorodithioate is obtained as 24 grams of pale amber oil EXAMPLE XXXVHI 5 (42 percent by weight of theory) by filtration of the undis- O,S-dimethyl S-[1,2-bis-(ethoxycarbonyl)ethyl] ill d id h h Hyflq h phosp lzorodztlnoate b EXAMPLE XLVH T e product in Example X,aboye, may also e pre- A pared by reacting potassium OSdimethsl phosphorodi O,S-d1methyl O-(4-mtloplzenyl)phosphorothlolafe thioate v(9.8 grams, 0.0 5 mole) with diethyl bromosuc- Tetramethylammonium O methyl 0 (4-nitrophenyl) cinate (12.7 grams, 0.05 mole) in 50 milliliters of refluxphosphorothioate (16.5 grams, 0.05 mole), melting point ing acetonitrile for thirty minutes. Potassium bromide 174 C., is dissolved in acetonitrile (250 cubic centiis filtered from the mixture and solvent removed from meters) by heating to 80 C., and then 0,0-dimethyl O- the filtrate in vacuo. The residue is dissolved in chloro- (4-nitrophenyl) phosphorothi na grams, form, Washed with 5 percent sodium bicarbonate solumole) is added all at once. Reflux is continued six hours. tion, and finally dried over magnesium sulfate. Solvent The by-product tetramethylammonium S-methyl O-(4- again is removed under vacuum, and the product identinitrophenyl) phosphorothiolate is recovered by filtration fied above recovered bydistillation. (14.8 grams, 89.2 percent by weight of theory, melting point 213 C.214 C.) and solvent evaporated from the EXAMPLES XXXDGXLV filtrate in vacuo. The residue consists of O,S-dimethyl The reactant salts in the following table and alkali 'P Y phosphorothiolate, grams (83-3 metal O,S-dimethyl phosphorodithioate percent by weight of theory). Analytically pure material,

CHSS SM 11 1.5 616, is obtained by molecular distillation.

25 EXAMPLE XLVIII O,S-dieth.ylO-(4nill'0phel1yl) phosphorothiolate wherein M is as shown in the table, are brought together Cyclohexylammonium O-ethyl O-(4-nitrophenyl) phosin equimolar proportions essentially as taught in Example phorothioate (18.1 grams, 0.05 mole) is suspended in XXXVIIT, above, and the corresponding esters produced: water milliliters) and diethyl sulfate (7.7 grams, 0.05

TABLE III Product Ester Exgmple Reactant Salts M R1A1 A2112 R XXXIXM'. ClCHzSC IL; Na... 0113s 01-130 -CI-IzSC2I-I XL BICH2CH2SC2H5 K CHQS' CHaO CH2CH2SC2H5 XLI ClCH2- Na CHsS 01130 -om xLrr ClCHz s02NHz Li CHsS CHsO CH2-S'O2NH2 O XLIII oiomN K 0113s 01 130 OHzN C1 or XLIV 010ml? 1 Li CIT-12S 01130 7 CH2N N i l N XLV 0101M -No1 K C1138 C1130 -OH2NO2 mole) is added dropwise. The resulting emulsion is heat- EXAMPLE XLVI 1 ed at 65 C75 C. for one hour, and then allowed to y 3 S Q f Y W y P separate. The upper aqueous layer is extracted twice with PhOrOdlf/Hoale chloroform and the extracts added to ,the main organic To an aqueous solution of potassium O methy1 s layer. This solution is washed with dilute sulfuric acid bis(ethoxycarbonyl)ethyl] phosphorodithioate, calculated and then with Water after which it is dned over magnesito contain 0.167 mole in 153 milliliters solution, is added dropwise 44 milliliters (0.3 34 mole) of ethyl sulfate. The

, mixture is heated to 50 C. and allowed to cool slowly.

The lower organic layer is removed, and the aqueous layer um sulfate. Solvent is removed under vacuum, and the liquid residue of O,S-diethyl O-(4-nitrophenyl) phosphorothiolate weighs 11.5 grams (79.1 percent by weight of theory), n 1.5492. Analytically pure material is ob extracted well with ether. The ether extracts are added to 7 tained by molecular distillation.

The results given in the following tables are indicative of the biological activity of the compounds of the present 15 While the above tables illustrate insecticidal and .miticidal activities of typical esters provided by the invention: present invention, it will be appreciated that the product TABLE IV Aphids, Mites, Milkweed Germ an Compound .01% 0.1% Bug, Roach,

1% Dust; 1% Dust CHaS 1 PSOH--GOOC2II5 98 100 100 100 CHaO CHa-C O O CzHs O HaS\fi (I? 2 PSCHzONHCH 100 100 80 TABLE V Aphids, Tribolium Milkweed German Mites, Compound 0.01% confusum, Bug, Roach, 0.1%

CZH5S\ O 1.... P

C2H50/ oNoi 95 100 100 100 100 CHsS\ 2.." P

CI'IaO \ONO2 100 100 100 100 100 2I-IaS\ O CHsO SCHCO 002115 100 72 95 100 CHzC O O C2115 The tests yielding the biological data in Tables IV and V, above, are as follows:

Nasturtium Aphid (A phis rumicus L.) .-The compounds to be tested are made up as 0.1% solutions in 65% acetone-% water. Pots containing nasturtium plants two inches tall and infested two days before are selected for testing. The pots are sprayed similarly for each test. Mortality estimates are made after holding for two days at 70 F., 50% RH, and compounds showing kills greater than 75% are further tested at tenfold dilutions in 65% acetone-35% water.

Confused Flour Beetle (Tribolium confusum Duv.). Compounds to be tested are made up as 1.0% dusts by mixing with talc. This dust is then brought into contact (similarly for each test) with confused flour beetles for three days at 80 F., 60% RH, following which mortality counts are made.

Large Milkweed Bug (Oncopeltus fasciatus Dall.).--

The 1% dusts described just above are used in this test and the bugs contacted therewith (similarly for each test). A small amount of moisture is also provided. Mortality counts are made after holding for three days at 80 F., 60% RH.

German Cockroach (Blattella germanica L.).--The procedure is the same as for the large Milkweed Bug; however, only adult males are used in this test.

Two-spotted Spider Mite (T etranychus telarius L.).- Compounds to be tested are made up as 0.1% solutions in 65% acetone-35% water. Sieva lima bean plants are infested with mites about five hours before testing. 'The infested leaves are dipped in the test solutions :and the plants allowed to dry. The treated plants are .held for two days at 80 F., 60% RH, and the mite mortality calculated. Compounds showing kills greater than 85% are further tested at ten-fold dilutions in 65% acetone-35% water,

esters contemplated herein manifest varying degrees of activity with respect to mites and particular insects. This can be observed to a certain degree from the above tables (see especially Compound 3 of Table V).

Clearly, the instant discovery encompasses numerous modifications within the skill of the art. Consequently, while the present invention has been described in detail with respect to specific embodiments thereof, it is not intended that these details be construed as limitations upon the scope of the invention, except insofar as they appear in the appended claims.

What is claimed is:

1. An organophosphorothioate ester of the formula R A SR wherein A and A represent a member selected from the group consisting of oxygen and sulfur; R represents a member selected from the group. consisting of lower alkyl and phenyl; R represents a member selected from the group consisting of lower alkyl 17' R represents a member selected from the group consisting of however, when A R is a member selected from the group consisting of lower alkoxy,

and

R is a member of the group above given other than lower alkyl, and when R is lower alkyl and R is a member selected from the group consisting of and wherein A and A each represent a member selected from the group consisting of oxygen and sulfur; R represents lower alkyl; R represents a member selected from the group consisting of l -CH2( JNCHa, -CHcOiH CHzQoOOz a M represents an ion selected from the group consisting of alkali metal ions, ammonium ions, monoalkyl (C -C ammonium ions; dialkyl (C C ammonium ions, trialkyl (C -C ammonium ions, cyclohexylammonium ions and dicyclohexylammonium ions; however, when M is alkali metal, R is other than a member selected from the group consisting of phenyl, benzyl and para-nitrophenyl. V

3. The cyclohexylammonium salt of O-ethyl O-(4- nitrophenyl) phosphorothioate.

4. The triethylammonium salt of O-ethyl O-(4-nitrophenyl) phosphorothioate.

5. The dibutylammonium salt of O-ethyl O-(4-nitro phenyl) phosphorothioate.

6. The hexylammonium salt of O-ethyl O-(4-nitrophenyl) phosphorothioate.

7. The alkali metal salt of S-[l,2-bis(ethoxycarbonyl)- ethyl] O-methyl phosphorodithioate. 8. The alkali metal salt of O-methyl S-(N-methylcarbam0y1)methy1 phosphorodithioate.

9. A method of preparing organophosphorothioate compounds which comprises bringing together in reactive contact in the presence of an inert solvent a thiophosphate ester of the formula and recovering the corresponding salt of the formula (C) R1Ai\ the symbols in the above formulae having the following meanings:

A A A A and A each represent a member selected from the group consisting of oxygen and sulfur; R represents a member selected from the group consisting of lower alkyl and phenyl; R and R each represent lower alkyl;

R and R each represent a member selected from the 7 group consisting of lower alkyl M represents an ion selected from the group consisting of alkali metal ions, ammonium ions, monoalkyl (C -C ammonium ions, dialkyl (C C ammonium ions, tri- =alkyl (C -C ammonium ions, cyclohexylammonium ions and dicyclohexylammonium ions.

10. The process of claim 9 wherein the salts (C) are reacted with a compound having the formula (R) Y, wherein R represents a member selected from the group consisting of lower alkyl,

Y is a member selected from the group consisting of halogen and SO and n is a value from 1 through 2, and recovering the corresponding ester conforming to the formula and 13. A method according to claim 9 in which-the reactant (A) is O-benzyl 0,0-diethyl phosphorothionate and the salt (C) recovered is the alkali metal salt of O-benzyl- O-ethyl phosphorothioate.

14. A method according to claim 9 in which the reactant (A) is S-[1,2-bis(ethoxycarbonyl)ethyl] 0,0-dimethyl phosphorodithioate and the salt (C) recovered is the alkali metal salt of S-[1,2-bis (ethoxycarbonyl)ethyl] O-methyl phosphorodithioate.

15. A method according to claim 9 in which the reactant (A) is 0,0-dimethyl S-(N-methylcarbamoyl)methyl phosphor-odithio-ate and the salt (C) recovered in the alkali metal salt of O-methyl S(N-methylcarbamoyl)- methyl phosphorodithioate.

16. A method of preparing organophosphorothioate compounds which comprises bringing together in reactive contact in the presence of an inert solvent a thiophosphate ester of the formula (A) RiAi S R30 A R with an organophosphoric acid salt of the formula (13) R4A4 As and an organic salt conforming to the formula )n and recovering the corresponding ester BIA, SR

O AzRg the symbols in the above formulae having the following meanings: A A A A and A each represent a member selected from the group consisting of oxygen and sulfur; R represents a member selected from the group consisting of lower alkyl and phenyl; R and R each represent lower alkyl; R and R each represent a member selected from the group consisting of lower alkyl 3,309,371 21 22 M represents an ion selected from the group consisting Y represents a member selected from the group consistof alkali metal ions, ammonium ions, monoalky1(C -C ing of halogen and --SO and n is a value from 1 ammonium ions, dialkyl (C -C ammonium ions, trithrough 2.

alkyl (C -C ammonium ions, cyclohexylammonium 5 References Cited by the Examiner ions and dicyclohexylammonium ions; R represents lower alkyl UNITED STATES PATENTS H 3,092,649 6/1963 Schrader 260-943 'CHzCNHCH OHgSCzH CHCOOC2H5, -CHgCHgSCgT-I 7 OTHER REFERENCES CHOOOCZH 10 Kosolapofi: Organo Phosphorus Compounds (1950), John Wiley & Sons, Inc., p. 256.

flip CHPGSONEI CHARLES B. PARKER, Primary Examiner.

s C O 1 15 FRANK M. SIKORA, RICHARD L. RAYMOND,

Assistant Examiners. OHzN 1 

1. AN ORGANOPHOSPHOROTHIOATE ESTER OF THE FORMULA 